Its well documented that using of histamine, acetylcholine and prostaglandin F2a directly on tracheal muscle (in vitro) caused tracheal muscle constriction as well as intravenous administration of these substances to animal (in vivo) causes bronchospasm accompanied by symptoms of dyspnea. This study was done in two sides: In vitro study, the aqueous extract of medicinal plants was used on tracheal muscle directly, three out often has a positive effect in tracheal smooth muscle relaxation. The aqueous extract of effective plants include, Cuminum cyminum (cumin), Thymus vulgaris (thyme) and Anthemis nobilis (chamomile) at a dose (0.4 mg/ml) for each planf which the mentioned dose induced tracheal smooth muscle relaxation in tracheal precontracted with histamine, acetylcholine and prostaglandin F2a at a dose (2 x 10~3 M) for each material. In vivo study, forty rabbit were used, divided into four groups (10 rabbit for each group). The aqueous extract of Cuminum cyminum (cumin) and Anthemis nobilis (chamomile) at a dose (1.5gm/kg) was given after half hour from histamine administration at a dose (0.4mg/kg) to induce bronchial smooth muscle constriction which accompanied by bronchospasm and dyspnea. The aqueous extract of Cuminum cyminum (cumin) and Anthemis nobilis (chamomile) which had been used led to bronchial smooth relaxation and relief of dyspnea. The laboratory findings indicated that histamine caused significant decrease in serum calcium levels in which the results were (7.95, 8.34, 8.78) u,g/dl in groups (2,3,4) respectively, in the same time magnesium results were (19.61, 20.2, 19.47) ug/dl in groups (2,3, 4) respectively and selenium results were (136.21, 137.98, 145.36) ug/dl in groups (2,3,4) respectively. The aqueous extract of Cuminum cyminum and Anthemis nobilis which had been used caused significant increase in serum calcium levels in which the results were (33.41, 97,62) u,g/di in groups (3,4) respectively, in the same time magnesium results were (74.91, 89.14) ug/dl in groups (3,4) respectively and selenium results were (302.69, 245.41) |ig/dl in groups (3,4) respectively. These results indicated clearly the possibility of using the aqueous extract of these plants to relief the bronchospasm in human after adjustment of the toxicity and adjustment the effective dosage.